FrostlineFelix

Seeing some assumptions in this thread worth correcting: Blade doesn't solve anything about cold-weather charging behavior. It's still LFP chemistry underneath the CTP packaging, and LFP's charge-acceptance cliff below freezing is a chemistry property, not a format property. If someone's chasing Blade thinking it'll behave differently than an EVE pack at -20°F, it won't. Same cold-weather charge cutoff considerations apply either way.

Everyone in this thread is fighting heat. I fight the opposite problem in Duluth. Cold does its own kind of quiet damage — charging an LFP pack below freezing without a warming circuit doesn't just slow things down, some BMS units will silently reject the charge entirely and you don't find out until you're stranded. If you're building anywhere that sees real winter, the thermal management conversation needs a cold-side plan as much as a hot-side one. Ask me how I found that out.

The Hyper-Heat performance numbers in this post track with what I've seen in Duluth, with one addition: at genuinely cold temps (below -15°F) I've watched output capacity derate noticeably even with defrost cycling working correctly — the unit is still heating, just not at its rated output. My backup resistance heat runs more than 8 hours a winter up here, closer to 40-60 depending on how brutal the season is. Great system. Just don't expect Idaho cold-weather numbers to hold at Minnesota cold.

The winter cooling-effect problem described here gets a lot worse the further north you go. In Duluth an unconditioned garage HPWH would be fighting an ambient air temperature that's below freezing for months, not just cool. Mine's in a conditioned basement space specifically because of this — the resistance backup would be running almost the entire winter otherwise, and at that point you're not saving much over a standard electric water heater.